Thailand will no longer delay new rail projects after a planned joint venture with China got bogged down, according to Prime Minister Prayut Chan-o-cha.
Gen Prayut said the construction of the line between Bangkok and Nakhon Ratchasima would be only the first step in a series of lines to come in the future.
"If we are still dragging our feet on this project, we will not catch up with other countries," he said in his Returning Happiness to All Thais weekly programme on Friday.
The prime minister told Chinese Premier Li Keqiang during their Mekong summit in Sanya in Hainan province on Wednesday that Thailand would go ahead with the train project without forming a joint venture with China.
The much-publicised project calls for a new line for medium-speed trains from Nong Khai to Map Ta Phut in Rayong and Bangkok. Thai and Chinese officials held a splashy ceremony in December to kick off the project, even though they were still at odds over the financial arrangements and the form of partnership the joint venture would take.
While Thailand will now fund the entire cost of the line, Gen Prayut said in China that China would construct the line to underline the still strong relations between the two countries.
The prime minister also made clear on Friday in his speech that the government had decided to scrap the original plan for a medium-speed track and would build a high-speed train line.
"The government places importance on having high-speed trains. We originally planned to lay tracks for a medium-speed train. But we have reached a conclusion that it is not suitable under present circumstances," he said.
But the launch date for construction of the first high-speed line linking Bangkok and Nakhon Ratchasima remains unclear. The prime minister expects work to start in July but Transport Minister Arkhom Termpittayapaisith told reporters earlier on Friday that construction would be possible in August or later.
The first train line will be the start of a programme to spur infrastructure investment and create more convenient options for public transport, he said. Trade, tourism and industries would also benefit from the line, he added.
The government plans to build other lines including one from Bangkok to Rayong and Chiang Mai to create a new, modern transport network in the country.
But Gen Prayut said that the focus now was on one line. "The network is a subject for discussion in later stages," he said.